How to make double-sided meshes where textures appear on both sides of the faces

I had this question myself, awhile back, and LHammonds gave me the answer. I thought I would post this here as a tutorial that can be easily linked to, if others need help with this in the future. I have created some screenshots here as a visual aid.

UPDATE: The latest version of Blender NIF Scripts reads the "Double Sided" button setting on each object and adds the NiStencilProperty for you now! Be careful though, the default on new objects is turned on and not always necessary. This tutorial is only informational now.

You must use NifSkope to make this change. There is no way to export a double-sided mesh from Blender.

Open NifSkope and the NIF

Right-click on the NiTriStrip/Shape that needs to be double-sided.

Node --> Attach Property --> NiStencilProperty

With the latest version of NifSkope, the "Draw Mode" property will be set to "DRAW_BOTH" and if not, you need to change it to that selection.

Save your NIF and you are done.

You can set a "double-sided" flag in Blender but it does not show both sides in it nor does export retain that setting so it is worthless in Blender for Oblivion modding.

When the NiStencilProperty is set in NifSkope, it will be immediately visible...no need to wait until you see it in-game.